In regards to games, you may also want to look at alternative stores than just Google/Apple.
There also seems to be a healthy market for game assets (3D models, textures, etc.) and multiple stores you can sell them in.
http://www.turbosquid.com/ https://www.assetstore.unity3d.com/en/
In regards to tutorials I have noticed many people using Patreon. Some seem to be making a decent passive income.